Famvir (famcicolvir) during 2nd and 3rd trimester - safe to take?

I'm an unfortunate sufferer from recurrent herpes (roughly 3/4 times a year). I had a flare-up during the first trimester and my ob/gyn said it was safe to take so I took the usual 5 day dose and it cleared up as usual.

I'm now 17 weeks and have been feeling as if I am about to have a flare-up for the last week but nothing's come through for definite yet. My ob/gyn is away for a few weeks and the advice from one of the GPs is that it's a category b drug (tested safely on animals but not yet humans) and so to err on the side of caution and not take it.

So, two questions for any fellow sufferers out there:1) Have you ever taken it during pregnancy and baby and you have been ok?2) Have you had a flare-up and not taken it and have the lesions/symptoms eventually gone away by themselves?

Appreciate that this is a fairly sensitive subject, so if you would prefer to PM a response, please feel free.